Reboot your machine in safe mode (by holding down the SHIFT key on restart). Your machine should start, but with reduced graphics and nothing loaded. Uninstall 3.5 and reinstall 3.4.2 ( search for it using google if you don't have the disk image saved on your machine).

Alternatively you could just reinstall Yosemite which should get 3.5 working, you just have to run the 10.10.1 and any other updates again. This may be quicker.

A reinstallation of Yosemite is a safe solution and is a lot better than holding down the shift key(safe mode) I agree completely as there may be some files that are missing from the Yosemite installation.

Same story here. Installed LS 3.5 on Mac Pro 2,1/Yosemite 10.10.1. Got blank screen after reboot. I was able to VNC/SSH to the mac, just to find that video card (Nvidia Geforce GT 640) does not detect any monitor connected (hence the only supported resolution was 1280x1024 or something similar). Tried everything with no effect. Found this thread, uninstalled Little Snitch (with the uninstaller provided), and boom, everything is working as expected again.

This happened to me many times: 50% after rebooting (when doing my usual running for a few days). The only thing that worked was a reinstall of Yosemite. The screen would sit with the activity indicator spinning and never get to the login screen. Running in verbose mode would show that it would hang at the AppleUSBMultiTouchDriver line.

I didn't know it was Little Snitch at the time and Apple replaced the logic board and the 1 TB SSD on 2 separate occasions. (I only noticed until much later that Little Snitch was always loaded before the hang happened. None of the Apple people noticed the Little Snitch loading text in verbose mode either.)

After removing Little Snitch it has not happened once. Unfortunately, I loved running Little Snitch but can't run it anymore until this problem has been tracked down and resolved. I sometimes come to these forums to see if the issue has been fixed. I dare not ever run Little Snitch on this machine again until it has.

All this has been fixed by Little Snitch without replying to my numerous emails when I complained that many users were having troubles with 3.5. One tech took down all my info (console etc) disappeared and was never heard from again. His name is Simon and will go down in infamy. Anyway they published an up date. HereIt Is. http://www.obdev.at/products/littlesnit ... notes.html They never replied to any further eMails.

jazzyguy wrote:All this has been fixed by Little Snitch without replying to my numerous emails when I complained that many users were having troubles with 3.5. One tech took down all my info (console etc) disappeared and was never heard from again. His name is Simon and will go down in infamy. Anyway they published an up date. HereIt Is. http://www.obdev.at/products/littlesnit ... notes.html They never replied to any further eMails.

This was happening before 3.5 for me.

The 3.5.1 update says, "Fixed an issue causing a first time installation of Little Snitch to hang under rare circumstances when attempting to restart the computer."

This was happening not just on a first-time installation for me.

I'm still concerned about installing Little Snitch again until this issue has been dealt with head-on and transparently.

jazzyguy wrote:I gave 3.5.1 a shot,It worked and I am a happy camper!!!!!!

I'm glad. It was to be expected. The kind of failure we experienced with 3.5 is very rare. Such things only happen on comparatively few machines when unexpected circumstances concur. After all, we can't expect small companies to own all Mac models with every conceivable configuration, as that would require hundreds or even thousands of test computers. Checking out every install programme on every computer would be crazy. Much as we liked LS 3.4.2 (the last stable version of LS before "our" 3.5 disaster), I recently read a guy for whom 3.4.2 was a nightmare. So you can never be absolutely sure, as you might be in the fringe minority for whom one given improvement fails to work as it should for reasons no programmer can foresee. The best we can expect is for a small company, such as obdev, to respond in a reasonable timeframe. In my experience, they have. So, no complaints from me. None whatsoever. Many thanks, obdev.

Odd, I updated my Little Snitch to 3.5.1 only to have my iMac unable to boot, including in Safe Mode! I've NEVER had a situation where I couldn't reboot into Safe Mode. While troubleshooting, I unplugged all my usb peripherals and voila! I replugged all my usb peripherals, only to have a problem with my keyboard, which was plugged into an external usb hub. Successfully logged in when I plugged keyboard into iMac itself. I am having some doubts now with Little Snitch, especially upon reading some of these comments regarding this problem.

jazzyguy wrote:Well EMR it is not a small company as you described. It owns Launch Bar and Little Snitch and other companies. Who doesn't have Launch Bar? Everyone has it in some manner across many OSs.

Not that I'm aware of other companies we own. Would be nice though We are a team of 10 people (not all of them full-time) so I would describe us as a rather small company.